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The product refresh leans, to a large extent, on IBM’s introduction of a series of storage enclosures that use the latest 3.0 generation of PCIe connectivity. But IBM seems to have stopped short of using the non-volatile memory express (NVMe) protocol that other array makers have leveraged.
The three arrays form part of the existing DS8880 series, but are suffixed F and comprise the DS8884F, DS8886F and DS8888F.
The DS8884 and DS8886 will still exist as hybrid flash arrays, without the F suffix. The DS8888 is already an all-flash array, but has an F added in this refresh.
Where previously the 4F and 6F were hybrid arrays with a range of spinning disk and flash drives possible, the new F models are all-flash, and use IBM’s High Performance Flash Enclosures Gen2 that use flash drives on PCIe cards.
The DS8884F offers between 6.4TB and 154TB of flash storage capacity, with 256GB of RAM. It is aimed at mid-range customers with targeted workloads, including enterprise resource planning (ERP), order processing, database transactions, customer relationship management (CRM) and human resource (HR) systems.
The DS8886F can have between 6.4TB and 614TB of capacity with 2TB of RAM. Suggested workloads include online transaction processing, high-speed commercial data processing, high-performance data warehouse and data mining, and critical financial transaction systems.
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The DS8888F also offers high performance, with 2TB of RAM and capacity from 6.4TB to 1.22PB. It and is aimed at workloads such as predictive analytics, real-time optimisation, machine learning and cognitive systems, and speech and video processing.
IBM’s Gen2 enclosures were announced in December 2016 and utilise the PCIe 3.0 interconnect. Gen 3 has bandwidth of around 1Gbps per lane – up to 16Gbps in a 16-lane configuration.
PCIe 3.0 is the basis for NVMe, which adds better traffic-handling characteristics to the performance gains of the new PCIe generation, and is the basis of NVMe-based array products such as EMC’s DSSD D5 and startup E8’s D24.
IBM could add NVMe functionality to its PCIe-based enclosures, but this would likely require upgrades to controller hardware that may currently be a bottleneck to further improved performance.
Quoted input/output operations per second (IOPS) for the F-suffixed arrays are 447,000 for the 8884F, 1.72 million for the 8886F and 1.975 million for the 8888F. These are all at 0.3μs (millisecond) latency with a load of 70% read/30% write, using 4Kb blocks and with a 50% read cache hit.
From supplied figures it’s not clear, however, at what capacity these figures apply.
Meanwhile, EMC claims IOPS figures north of 10 million for its DSSD D5 rack-scale flash arrays with 100μs latency, but that’s across 36 flash modules.